Mitsubishi Montero (2002-2004). Manual — part 750

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SYMPTOM PROCEDURES

13Ad-49

STEP 4. Inspection of throttle body (throttle valve area) for
dirtiness.
Q: Is the throttle valve area dirty?

YES : Refer to GROUP 13A, On-vehicle Service

− Clean the

throttle valve area

P.13Aa-11

.

NO : Check the following items, and repair, replace or

clean the defective sections.

a. Check the ignition coil, spark plugs, spark plug

cables.

b. Check the EGR valve.

Then confirm that the malfunction symptom is

eliminated.

INSPECTION PROCEDURE 15: Hesitation, sag or stumble.

.

COMMENT

• In cases such as the above, the ignition system,

air/fuel mixture, electronic control throttle valve
system or compression pressure may be defec-
tive.

.

TROUBLESHOOTING HINTS (The most likely
causes for this case: )

• Malfunction of the ignition system.

• Malfunction of air/fuel ratio control system.

• Malfunction of the electronic control throttle valve

system.

• Malfunction of the fuel supply system.

• Malfunction of the EGR system.

• Poor compression pressure.

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, read the diagnostic
trouble code (DTC).

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC set?

YES : Refer to GROUP 13A, Diagnostic Trouble Code Chart

P.13Ab-2

.

NO : Go to Step 2.

ACX01539

16-PIN

MB991502

AC

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SYMPTOM PROCEDURES

13Ad-50

STEP 2. Using scan tool MB991502, check actuator test
items 01, 02, 03, 04, 05, 06: Injector.
(1) Check following items in the actuator test. Refer to GROUP

13A, Actuator Test Reference Table

P.13Ab-42

.

a. Item 01, 02, 03, 04, 05, 06: Injector.

(2) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operating properly?

YES : Go to Step 3.
NO : Refer to GROUP 13A, DTC P0201, P0202, P0203,

P0204, P0205, P0206

− Injector Circuit

P.13Ac-318

.

STEP 3. Check the ignition timing.
(1) Refer to GROUP 11A, On-vehicle Service

− Ignition Timing

Check

P.11A-6

.

Q: Is the ignition timing normal?

YES : Go to Step 4.
NO : Check that the crankshaft position sensor and timing

belt cover are in the correct position. Then confirm
that the malfunction symptom is eliminated.

STEP 4. Using scan tool MB991502, check data list and
actuator test.

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check the following items in the data list. Refer to GROUP

13A, Data List Reference Table

P.13Ab-29

.

a. Item 13: Intake Air Temperature Sensor.
b. Item 25: Barometric pressure Sensor.

c. Item 21: Engine Coolant Temperature Sensor.

d. Item 69: Right Bank Heated Oxygen Sensor (rear).
e. Item 39: Right Bank Heated Oxygen Sensor (front).

f. Item 59: Left Bank Heated Oxygen Sensor (rear).

g. Item 11: Left Bank Heated Oxygen Sensor (front).

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are they operating properly?

YES : Go to Step 5.
NO : Repair or replace. Then confirm that the malfunction

symptom is eliminated.

ACX01539

16-PIN

MB991502

AC

ACX01539

16-PIN

MB991502

AC

TSB Revision

SYMPTOM PROCEDURES

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STEP 5. Using scan tool MB991502, check data list.
(1) Turn the ignition switch to the "ON" position.
(2) Check the following items of data list. Refer to GROUP 13A,

Data List Reference Table

P.13Ab-29

.

a. Item 39: Right Bank Heated Oxygen Sensor (front).
b. Item 11: Left Bank Heated Oxygen Sensor (front).

• Voltage should fluctuate between 0 − 0.4 volts and 0.6 −

1.0 volts while idling after the engine has warmed-up.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?

YES : Go to Step 7.
NO : Go to Step 6.

STEP 6. Check the fuel pressure.
Refer to GROUP 13A, On-vehicle Service

− Fuel Pressure Test

P.13Aa-13

.

Q: Is the fuel pressure normal?

YES : Check the following items, and repair or replace the

defective items.

a. Vacuum leak.

• Broken intake manifold gasket.

• Broken air intake hose.

• Broken vacuum hose.

• Positive crankcase ventilation valve does

not operate.

b. Injector clogged.

Then confirm that the malfunction symptom is

eliminated.

NO : Repair or replace. Then confirm that the malfunction

symptom is eliminated.

STEP 7. Check the fuel pressure.
Refer to GROUP 13A, On-vehicle Service

− Fuel Pressure Test

P.13Aa-13

.

Q: Is the fuel pressure normal?

YES : Check the following items, and repair or replace the

defective items.

a. Check the ignition coil, spark plugs, spark plug

cables.

b. Check the EGR system.

c. Check compression pressure.

d. Check the fuel filter or fuel line for clogging.

Then confirm that the malfunction symptom is

eliminated.

NO : Repair or replace. Then confirm that the malfunction

symptom is eliminated.

ACX01539

16-PIN

MB991502

AC

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SYMPTOM PROCEDURES

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INSPECTION PROCEDURE 16: Acceleration shock.

.

COMMENT

• There may be an ignition leak accompanying the

increase in the spark plug demand voltage during
acceleration or the electronic control throttle
valve system failed.

.

TROUBLESHOOTING HINTS (The most likely
causes for this case: )

• Malfunction of the ignition system.

• Malfunction of the electronic control throttle valve

system.

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, read the diagnostic
trouble code (DTC).

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC set?

YES : Refer to GROUP 13A, Diagnostic Trouble Code Chart

P.13Ab-22

.

NO : Check the following items, and repair or replace the

defective items.

a. Check the ignition coil, spark plugs, spark plug

cables.

b. Check for occurrence of ignition leak.

Then confirm that the malfunction symptom is

eliminated.

ACX01539

16-PIN

MB991502

AC